[gnome-shell] Util: fix binary search exit condition

[Giovanni Campagna <gcampagna src gnome org>]

commit bbdce159fad472cc22073bf064037992b187d0b2
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Tue Dec 20 21:30:30 2011 +0100

    Util: fix binary search exit condition
    
    The loop can exit with an interval of length one or one of
    length zero. In the first case it is correct to check which side
    of the interval to return, in the second case no comparison should
    be made (since there is only one possible value).
    In practice, this usually results in one comparison more than needed,
    but in some cases (when the position was past the end of the array),
    would call the comparator with undefined.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=666614

 js/misc/util.js            |    2 +-
 tests/unit/insertSorted.js |    7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/js/misc/util.js b/js/misc/util.js
index 3664058..8673f83 100644
--- a/js/misc/util.js
+++ b/js/misc/util.js
@@ -265,7 +265,7 @@ function lowerBound(array, val, cmp) {
             max = mid;
     }
 
-    return (cmp(array[min], val) < 0) ? max : min;
+    return (min == max || cmp(array[min], val) < 0) ? max : min;
 }
 
 // insertSorted:
diff --git a/tests/unit/insertSorted.js b/tests/unit/insertSorted.js
index e23848a..610aeed 100644
--- a/tests/unit/insertSorted.js
+++ b/tests/unit/insertSorted.js
@@ -64,8 +64,13 @@ let arrayEmpty = [];
 // inserting in a empty array
 Util.insertSorted(arrayEmpty, 3, checkedCmp);
 
+// Insert at the end and check that we don't
+// access past it
+Util.insertSorted(arrayEmpty, 4, checkedCmp);
+Util.insertSorted(arrayEmpty, 5, checkedCmp);
+
 // Some more insertions
 Util.insertSorted(arrayEmpty, 2, checkedCmp);
 Util.insertSorted(arrayEmpty, 1, checkedCmp);
 
-assertArrayEquals('checkedCmp test', [1, 2, 3], arrayEmpty);
+assertArrayEquals('checkedCmp test', [1, 2, 3, 4, 5], arrayEmpty);